A major problem associated with hot-fillable blow-molded containers is the need to accommodate changes in the container configuration due to reductions in volume as the hot-filled liquid cools alter the container has been capped. Some prior art approaches to solving this problem involve the use of flex panels at various locations in the container side wall. Flex panels are designed to move in response to reductions in volume in the containers so that the filled level of the liquid remains at a pre-determined location.
Examples of containers having such panels may be found in U.S. Pat. Nos. 4,749,092; 4,805,788; and 4,946,053. Two recently issued patents having hand grips with flex panels formed in the hand grips are disclosed in U.S. Pat. Nos. 5,141,120 and 5,341,121. Other collapse-resistent containers are disclosed in U.S. Pat. Nos. 3,923,178; 4,381,061; 4,387,816; and 4,610,366. Containers having recessed sidewalls providing handgrips are disclosed in U.S. Pat. No. D282,050.
Although various ones of the referenced containers may function satisfactorily for their intended purposes, there is a need for blow-molded plastic containers which not only accommodate reductions in volume due to cooling of a hot-filled liquid, but which also retain their structural integrity after being opened by a consumer and contents poured from the container. In other words, a desirable container should also be capable of retaining its intended shape when gripped hiring pouring and handling. Furthermore, such a container should also be capable of being molded with a minimum of plastic to minimize costs.